Although my daughter has a degree in microbiology I sadly do not. I will use the vulgarization I know and may make errors in the terms. For this reason any new info I find will be accompanied by info from professionals.

The document cited above is of interest although it is not concerning rabies in Canada. I don't know how many strains of rabies have existed through out history there is a graphic on this website.

In some Canadian documents they state that in the 80s the variant of rabies was fox rabies probably indicating the principal reservoir however this was also carried by skunks. This document states they were the principal carrier in the states.

My daughter worked making vaccines but has recently changed branches as she got a second University degree and is working in another domain. I am familiar to some of the terms in this document because of that. The most interesting info I found and was not aware of was that some "attenuated" bait vaccines were actually making animals sick. When a virus is attenuated it is simply a weaker version of itself (vulgarized obviously).

"The raccoon rabies epizootic in the eastern United States provided renewed impetus for reconsidering oral vaccination technology, first conceived at the Center for Disease Control in the 1960s (34). The shift of the vaccination and baiting methods from a fox model to the raccoon involved extensive field and laboratory research during the 1980s. The existing attenuated rabies vaccines for foxes were shown to be less effective for raccoons and other carnivores (35,36). Additionally, studies of new candidate vaccines raised safety issues regarding vaccine-induced disease in wildlife (36)." Quote from: The Ascension of Wildlife Rabies: A Cause for Public Health Concern or Intervention?

In this article they speak of dog to dog transmission of the variant of rabies which according to them was mostly carried by a certain type of skunk but commonly referred to as the fox variant before the raccoon variant became more widely spread.

Just like raccoon denned in barns according to the previous article, when I was young skunks often wandered into the yard and found their way into the garbage cans. As a young teen our dog was sprayed by a skunk. We unfortunately had a couple of garbage cans behind the house and had not noticed the skunks foraging when we let the dog out.